Code reader

Abstract

An identification device, especially one for detecting unidimensional and / or two-dimensional codes, which has a position-resolving photoreceiver arranged in a housing and a reception optics coordinated with it and also installed in the housing. The entire reception optics and the position-resolving photoreceiver are immovably mounted in a housing of the identification device. For focusing at different object distances, an effective optical back focal distance is changed with only an adjustable deflection mirror that is positioned between the photoreceiver and the reception optics.

Description

BACKGROUND OF THE INVENTION [0001] The invention concerns an identification device, and especially a code reader, for detecting unidimensional and / or two-dimensional codes with a position-resolving photoreceiver and associated reception optics installed in a housing. [0002] Known identification devices of this type have reception optics that project in its focal plane an image of a code in the object plane. A position-resolving photoreceiver is situated in the focal plane which has several photoreceiver pixels arranged in line or matrix form. [0003] The different contrasts in the code and, consequently, also in the image of the code generate different photocurrents in the individual photoreceiver pixels, from which the contents of the code can be identified with appropriate signal processing. [0004] Such codes are used in a variety of applications, such as for identifying and controlling individual objects on conveyors. The code is not limited to any particular kind of code and incl...

AI Technical Summary

Benefits of technology

[0016] Another advantage of the invention is that the mechanical connections needed to adjust the deflection mirror in the housing of the identification device can consist of only one or more pivot joints, which are economically and technically superior to sliding or cam-operated connections. This advantage exists both when the deflection mirror is mounted on a swivel arm and when it is mounted on a four-bar linkage. Since these pivot joints move over a limited range of pivot angles, flat, flexible spring strips can be substituted for the pivot joints. When the spring strip involves a crossed strip arrangement, a well-defined, play-free rotary bearing function is obtained, which assures a stable and wear-free rotary movement for long periods of time.

is that the mechanical connections needed to adjust the deflection mirror in the housing of the identification device can consist of only one or more pivot joints, which are economically and technically superior to sliding or cam-operated connections. This advantage exists both when the deflection mirror is mounted on a swivel arm and when it is mounted on a four-bar linkage. Since these pivot joints move over a limited range of pivot angles, flat, flexible spring strips can be substituted for the pivot joints. When the spring strip involves a crossed strip arrangement, a well-defined, play-free rotary bearing function is obtained, which assures a stable and wear-free rotary movement for long periods of time.

Problems solved by technology

The relatively large mass of the components of fast reading, long-focal-length receiving lenses limits the speed with which they can be moved.

Such systems are further subject to mechanical stresses in the region of their bearings and are not well suited for continuous use over long periods of time.

Furthermore, this focusing method is generally time-consuming and is therefore not well suited for responding to rapidly changing code distances.

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